The present invention relates to a data storage device having a recording medium such as a disk and a method of manufacturing the same. More particularly, the present invention is concerned with a data storage device improved in interior sealability and a method of manufacturing the same.
Devices using various types of media such as optical disks and magnetic tapes are known as information recording and reproducing devices. Among them, hard disk drives (HDDs) have become popular as storage devices for computers to such an extent that they are one of the storage devices indispensable for today's computers. Further, not limited to computers, their application is widening more and more due to the superior characteristics with the advent of moving picture recording/reproducing devices, car navigation systems, removable memories for digital cameras and so on.
A magnetic disk used in HDD has plural concentric tracks. Address information (servo information) and user data are stored in each track. A magnetic head formed by a thin film element makes access to a desired area (address) in accordance with address information, whereby data can be written or read. In a data read processing, a signal read from the magnetic disk by the magnetic head is subjected to a predetermined signal processing such as waveform shaping or decoding in a signal processing circuit and is then transmitted to a host. Data transferred from the host is likewise subjected to a predetermined processing in the signal processing circuit and is then written to the magnetic disk.
The components concerned are housed within a hermetically sealed case composed of a base for carrying the components thereon and a cover for covering an opening of the case. The interior of HDD is maintained in a high degree of cleanness to ensure the reliability of head-disk interface. Further, environment temperature, humidity or moisture condensation exerts a great influence on the reliability of HDD, such as dust. Therefore, there is adopted a method, for example, wherein a packing is inserted into a base-cover boundary, then the base and the cover are lapped together through the packing and are united using screws.
For reducing the cost of HDD there also is known a method wherein a sheet metal base is used, a cover is put over the opening of the base like the dropping lid used in cooking, and an upper surface of the cover is covered with a sealing tape (this method will hereinafter be referred to as the sealing method) (see Patent Document 1, Japanese Patent Laid-Open No. Hei 10(1998)-334641).
For example, in a storage device described in Patent Document 1, a cover is formed so as to be fitted on an inner periphery surface of a base in such a manner that an upper end face of the cover is substantially flush with an upper end face of the base without projecting upward from the upper end face of the base. Therefore, the sealing tape becomes easier to be affixed to the sealed portion to improve workability.